匿名类型没有明确键（`新的{}标识符`）的语法？

问题描述

在这个问题我看到一个陌生的语法匿名类型表达式：

 新{MyObjectID = g.Key，totalSum} 
  

起初我以为它（，totalSum} ）是一个语法错误，因为没有密钥被指定，但它编译并工作在C＃3.0。我在LINQPad（2.X - > C＃3）证实了这一语法：

  VAR Y =:-) ; 
变种Q =新的{Y = Y，Y，y.Length，}; 
 q.Dump（）; 
  

结果：

 （匿名类型）{
 Y =:-)，$ b $通过=:-)，
长度= 3 
} 
  

凡在规范这个语法定义？（答案应包括适用的参考和相应的摘录。）

和，更主观的（随意不回答），这是一个好的语法/捷径省略钥匙？我没有用它，只要我不认识它，而且我不是很迷恋与语法糖。

解决方案

7.6.10.6匿名对象创建表达式

（第181页）

在简单来说，这表示，如果你不提供自己的标识符，编译器将选择用于表达最后成员标识作为默认值。

至于如果它是好还是坏...好，我倒是恰恰避免这样做，以排除其他人谁不知道这个快捷键是一头雾水。

In this question I saw an anonymous type expression with an unfamiliar syntax:

new { MyObjectID = g.Key, totalSum }

At first I thought it (, totalSum }) was a syntax error as no key is specified, but it compiles and works in C#3.0. I have verified this syntax in LINQPad (2.x -> C#3):

var y = ":-)";
var q = new { Y = y, y, y.Length, };
q.Dump();

Result:

(anon type) {
  Y = ":-)",
  y = ":-)",
  Length = 3
}

Where in the specification is this syntax defined? (Answers should include an applicable reference and appropriate excerpt.)

And, more subjective (feel free not to answer), is it a good syntax/short-cut to omit the keys? I have not used it so far as I have not known about it, and I am not very enamored with that syntactical sugar.

解决方案

7.6.10.6 Anonymous object creation expressions

identifier                           expr . identifier

identifer = identifier               identifier = expr . identifier

(page 181)

In simple terms this says that if you don't provide an identifier yourself, the compiler will select the identifier for the "last" member of the expression as a default.

As for if it's good or bad... well, I 'd avoid doing it precisely to rule out the possibility that someone else who doesn't know this shortcut is confused.

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